Evaluation of target options for advanced radiography facilities

Initial results indicate that electron beams hitting targets used to generate X-rays during multipulse operation in advanced radiography facilities will generate plasma plumes which will disturb the electron beam during subsequent pulses. This, in turn, potentially can degrade the X-ray spot quality generated by the subsequent pulses. If this concern is substantiated, new facilities such as the Advanced Hydrotest Facility (AHF) will need a provision for mitigating this effect. One such provision involves moving the target with sufficient velocity that any plasmas formed are carried adequately far from the electron beam that they do not disturb it. We report the various approaches which have been considered and present data showing the maximum target rates which can be achieved with each approach